1. Field of the Invention
The present invention relates to an image forming apparatus, for example, of an ink jet system, and a sealing mechanism of an ink channel, which is disposed in an ink channel to supply an ink liquid stored in a container to an ink head and which seals the ink channel, for example, at the time of a replacing operation of the ink head.
2. Description of the Background Art
In an image forming apparatus of an ink jet system, an ink liquid stored in an ink tank is supplied to an ink head, and the ink liquid is spouted from the ink head. The spouted ink liquid is shot onto an image forming medium. Accordingly, an image is formed on the image forming medium.
A method of supplying the ink liquid to the ink head from the ink tank is described, for example, in Jpn. Pat. Appln. KOKAI Publication No. 2000-103084. In the Jpn. Pat. Appln. KOKAI Publication No. 2000-103084, at the time of an image forming operation, a pump for circulating ink is driven to thereby supply the ink liquid stored in the ink tank to the ink head. When air is mixed in the ink liquid in spouting the ink liquid from the ink head, a trouble is caused in the spout of the ink liquid by the ink head. A method of removing the air in the ink liquid in this situation has been described.
To remove the air in the ink liquid, the air included in the ink liquid is floated upwards utilizing buoyancy of the air, and captured. That is, the air included in the ink liquid is trapped in a vertical portion of a bypass pipe through a spatial portion above the ink head. During forced circulation of the ink liquid, an opening/closing valve disposed on the bypass pipe is opened, and the pump for circulating the ink is driven. Accordingly, the ink liquid returns to the ink tank through the bypass pipe. Accordingly, the air is blown into the ink tank. The air is separated from the ink liquid in the ink tank.